Author Topic: New 69 Z28 302 rebuild, dizzy has rev limiter. What is the best RPM limitation?  (Read 21876 times)

doomer

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I respect the fact that there are opinions regarding the use of rev limiters. However, there is one on my DZ 302 now, so I am seeking some sage advice on what it should be set to?

I recently had the engine rebuilt (original numbers). I am now at .060 over. I tried very hard to stay original on everything. However, the distributor needs work, so I replaced it with a petronics setup that looks rather stock, but includes the electronic setup and rev limiter.

What would be the ideal set point for the rev limiter?


Shane

janobyte

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Relative question ,what are you doing with it ? Racing ,cruising with an occasional bang through the gears ? On the race car we run a 2 step 1st to flash the convertor at launch, 2nd a few hundred past point were power curve starts coming down/shift point.  On the street I plan on 6800 to keep it safe with the 4 gear, plus according to my cam sheet power begins to fall off. They may be able to take a 8 grand spin ,but do you really want to push it ? Don't make a habit of "stuttering the engine " Even on the 1st stage I leave on the tac just under the chip. Very hard on the engine otherwise.
68 Z/28  born with: 302, drive line, etc..

69Z28

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I'm curious about this topic as well. At some point I'll be putting my 302 back in my Z. It will be all stock except .030 overbore. Distributor is all rebuilt and ready to install, carb is all done. I want to use a rev limiter and haven't the slightest idea what I should purchase that isn't gonna stick out like a sore thumb. I like the all in one set up for the distributor like Shane has but I have money tied up in the stock 480 rebuild and set up as well as a Dave's Smallbody HEI set up to specs per JohnZ's articles.

To answer Shanes question...on where to set the limit...I was going to stick between 6500 and 7200 RPM on mine. I have been up to 75-7600RPM before but don't want to go that far anymore.


So if anybody has any idea on a stand alone type rev limiter post it here. I had an older Mallory unit years ago that had a dial mounted under the dash that was wired to a small box in the engine compartment, but I'll be damned if I can't find it now.
GaryC

'UNRESTORED' 1969 Cortez Silver Z28 X33 D80

janobyte

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Adding to I ran a Mallory Rev limiting Tac for years in the Z, still have it. Worked great and would dial down to 0 when I left the car. 1 setting for limit ,one  for shift light.
68 Z/28  born with: 302, drive line, etc..

janobyte

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We run a MSD box in the Anglia, 500 increment chips, soft touch. You can hide the box under passenger seat. Check their website for specs ,works with points.
68 Z/28  born with: 302, drive line, etc..

69Z28

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Adding to I ran a Mallory Rev limiting Tac for years in the Z, still have it. Worked great and would dial down to 0 when I left the car. 1 setting for limit ,one  for shift light.


I've seen those too. What if you have the in dash tach?  I might hit ebay to see what is available in vintage form for Mallory.

The piece I have was once in a friends car and when a bunch of us would go out with him in his car we were always screwing with the dial. He would start up the road normal and then dump it and the engine would break up at 2500 RPM or even lower and he would come unglued wondering what the heck just happened. He finally caught on it was us f'n with him. It was funny to see him get bent out of shape thinking there was something terribly wrong with his fresh engine.
GaryC

'UNRESTORED' 1969 Cortez Silver Z28 X33 D80

69Z28

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We run a MSD box in the Anglia, 500 increment chips, soft touch. You can hide the box under passenger seat. Check their website for specs ,works with points.

Which unit are you using? I have some time to look on line right now. Might as well check into it.
GaryC

'UNRESTORED' 1969 Cortez Silver Z28 X33 D80

cook_dw

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Like others have already said.  It really depends on what you are gonna do with the car.

janobyte

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Which unit are you using? I have some time to look on line right now. Might as well check into it.



6a, which I plan on robbing for the Z . They have a new unit out where you can control everything including different ramps for timing via laptop ,around $500-600.  Very affordable tech for bracket racers. My buddy has a 8.9 72 Camaro his daughter races at mid 9's. We both run locked out distributors and hard starts when at operating temps have been cured. He's sold.
I'm giving it a try next spring. I need to take some more hit out at the line.

My Sun Tac is mounted in dash ( fuel gauge spot) has been 44 years. I had the Mallory, oil/water temp gauges mounted on the cowl. With the glass snorkel hood really had that old super stock look. I did have issues with the MSD dial accessory to control rev and went back to the chips.(Anglia ,I'm bouncing between cars)

These 302's can take a ton of abuse with only high REV issues I'm aware of being in the valve train. Also heavy pistons . Strong crank and rods.(Relieved of course now) My dad shifted at 8200 ,other than some ignition and traction issues she lived to see another day, that was in the 70's and hasn't seen that kind of abuse since. That being said ,today It's staying under 7 grand----you can pickup a dressed 383 crate motor for what one of these blocks are worth.
68 Z/28  born with: 302, drive line, etc..

69Z28

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Which unit are you using? I have some time to look on line right now. Might as well check into it.



6a, which I plan on robbing for the Z . They have a new unit out where you can control everything including different ramps for timing via laptop ,around $500-600.  Very affordable tech for bracket racers. My buddy has a 8.9 72 Camaro his daughter races at mid 9's. We both run locked out distributors and hard starts when at operating temps have been cured. He's sold.
I'm giving it a try next spring. I need to take some more hit out at the line.

My Sun Tac is mounted in dash ( fuel gauge spot) has been 44 years. I had the Mallory, oil/water temp gauges mounted on the cowl. With the glass snorkel hood really had that old super stock look. I did have issues with the MSD dial accessory to control rev and went back to the chips.(Anglia ,I'm bouncing between cars)

These 302's can take a ton of abuse with only high REV issues I'm aware of being in the valve train. Also heavy pistons . Strong crank and rods.(Relieved of course now) My dad shifted at 8200 ,other than some ignition and traction issues she lived to see another day, that was in the 70's and hasn't seen that kind of abuse since. That being said ,today It's staying under 7 grand----you can pickup a dressed 383 crate motor for what one of these blocks are worth.


So a nothing special rev limiter is a 6A? I don't want to do anything different to the engine once I get it were I like it, and I guess a basic keep me out of trouble limiter would work just fine. Nothing high dollar, this is budget time for me.
GaryC

'UNRESTORED' 1969 Cortez Silver Z28 X33 D80

cook_dw

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Like the OP listed..  Pertronix has been around for a while & this is just making a great product better.

http://www.pertronix.com/support/videos/ignitor/install-i3/default.aspx

janobyte

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6AL is  the control box so to speak, small chips ,which are actually resistors , plug in for quick change on the side. They come in an assortment of numbers ,I'm not getting into a product debate because I'm not on MSD's payroll. Yes Pertronix has a great rep and offers a clean , stock appearing upgrade. Back to your original question, IMO keep it under 7 grand.
68 Z/28  born with: 302, drive line, etc..

cook_dw

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,I'm not getting into a product debate because I'm not on MSD's payroll. Yes Pertronix has a great rep and offers a clean , stock appearing upgrade. Back to your original question, IMO keep it under 7 grand.

That was not my intent..  Just stating that for a stock appearance to go under the cap the pertronix is a nice product.  If I was doing it my way I would use the 6AL box.. ;D

janobyte

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No problem, I tend to rant when talking performance mods, the pen units do seem to offer the best bang for the buck while keeping it looking stock and clean, not firing a 14:1 engine.
68 Z/28  born with: 302, drive line, etc..

doomer

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Relative question ,what are you doing with it ? Racing ,cruising with an occasional bang through the gears ?

You got it! Cruising with an occasional bang through the gears. I may run it up the strip on a drag night with my club just for fun, but not often. I'm after a little insurance against missing a clean shift/gear wherever I may be.

BTW, my bad on the spellun... Pertronix.

So as I understand it, the advice here seems to be between 6800 and 7200? It was set at 7100, although for some reason, it seems to be cutting in at 5100 right now. I am going to take a closer look as soon as I get a chance.

Great info all around, thanks folks!

Shane
« Last Edit: October 15, 2013, 12:20:53 PM by doomer »